The LB&SCR (London, Brighton and South Coast Railway) I1 class was a class of 4-4-2 atlantic steam tank locomotives designed by D. E. Marsh for suburban passenger services. In total 20 were built between 1906-1907, being rebuilt into I1X tank locomotives from 1925-1932, they boasted 17,430 pounds of traction effort. This class was intended to haul secondary passenger trains, especially in the south London suburbs, and the twenty locomotives were constructed by Brighton works between June 1906 and December 1907. The locomotives proved to be reliable but with disappointing performance in their original form, being poor steamers, but all of them passed to the Southern Railway in 1923. They reportedly gained the nickname "wankers" due to their poor steaming capabilities. Two worn-out members of the class were withdrawn by the Southern Railway in 1944 and 1946 respectively, but the remainder survived into BR (British Railways) ownership in 1948, although all had been withdrawn by July 1951 and, unfortunately, none have been preserved.